1. Field of the invention
The invention concerns time-division switching systems, especially multiservice key telephone or PABX systems.
2. Description of the prior art
These systems provide selective and on-demand transmission of information between telecommunication terminals connected to them. They are able to function either in isolation or within telecommunication networks made up of identical or compatible systems.
Each system has an internal switching network to the inputs and outputs of which are connected terminations for telephone links providing interconnection to other systems and/or for information communication terminals. The switching network of a known time-division switching system stores temporarily the information that it switches, the information being broken down into successive samples for this purpose.
A timebase synchronizes memorization and transmission of samples by the switching network.
Control logic sets up communications between terminations through the switching network. It usually comprises at least one management processor associated with dedicated auxiliary equipments performing the various tasks involved in the functioning of the system.
These auxiliary equipments often comprise processors implementing specific functions for which they are sometimes specifically structured.
This results in systems with hardware and software architectures incorporating redundancies and anomalies which generally increase with time as modifications are made to meet changing user requirements. Systems of the same design therefore tend to become increasingly diversified and their operation tends to become degraded.